In 1987 Irving Sloane patented a new design for classical guitar tuning machines to eliminate gear backlash. He designed the machines to look better and work better than any others. Soon afterwards he utilized his wealth of knowledge and redesigned these patented machines for the string bass.

The central aspect of the patent is the built-in handle tensioning system. The system is a simple nut and washer assembly at the base of the handle that not only allows for variable "feel" while tuning, but also for quick and inexpensive handle replacement. Irving Sloane Bass Machines features include: